MCQOPTIONS
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MCQOPTIONS
This section includes 46 Mcqs, each offering curated multiple-choice questions to sharpen your VITEEE knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In an AC circuit, resonance occurs when |
| A. | Resistance equals reactive reactance |
| B. | Capacitive reactance equals resistance |
| C. | Capacitive reactance equals inductive reactance |
| D. | Resistance equals capacitive and reactive reactance |
| Answer» D. Resistance equals capacitive and reactive reactance | |
| 2. |
An alternating voltage v(t) = 220 sin 100πt volt is applied to a purely resistive load of 50 Ω. The time taken for the current to rise from half of the peak value to the peak value is: |
| A. | 5 ms |
| B. | 2.2 ms |
| C. | 7.2 ms |
| D. | 3.3 ms |
| Answer» E. | |
| 3. |
A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2 kW. If the current in the secondary coil is 10 A, then the input voltage and current in the primary coil are: |
| A. | 220 V and 20 A |
| B. | 440 V and 20 A |
| C. | 440 V and 5 A |
| D. | 220 V and 10 A |
| Answer» D. 220 V and 10 A | |
| 4. |
A light bulb and an open coil induction are connected in series to an ac source as shown in figure. Now an iron rod is inserted into the interior of the inductor. The glow of the light bulb |
| A. | decreases |
| B. | increases |
| C. | unchanged |
| D. | bulb will be fused |
| Answer» B. increases | |
| 5. |
In an AC circuit V = 100 sin (100t) volts and\(I = 100\sin \left( {100t + \frac{\pi }{3}} \right)mA\). The power dissipated in the circuit is |
| A. | 104 W |
| B. | 2.5 W |
| C. | 10 W |
| D. | 5.0 W |
| Answer» C. 10 W | |
| 6. |
In the figure shown below, the charge on the left plate of the 10 μF capacitor is -30 μC. The charge on the right plate of the 6μF capacitor is |
| A. | +12 μC |
| B. | +18 μC |
| C. | -12 μC |
| D. | -18 μC |
| Answer» C. -12 μC | |
| 7. |
A circuit connected to an ac source of emf e = e0 sin (100t) with t in seconds, gives a phase difference of \(\frac{\pi }{4}\) between the emf e and current i. Which of the following circuits will exhibit this? |
| A. | RL circuit with R = 1 kΩ and L = 10 mH |
| B. | RL circuit with R = 1 kΩ and L = 1 mH |
| C. | RC circuit with R = 1 kΩ and C = 1 μF |
| D. | RC circuit with R = 1 kΩ and C = 10 μF |
| Answer» E. | |
| 8. |
In a step-up transformer, the value of current in the secondary coil in comparison to primary coil is |
| A. | Equal |
| B. | Less |
| C. | More |
| D. | There is no relation |
| Answer» C. More | |
| 9. |
A mixture of 2 moles of helium gas (atomic mass = 4 u), and 1 mole of argon gas (atomic mass = 40 u) is kept at 300 K in a container. The ratio of their ‘rms’ speeds \(\left[ {\frac{{{V_{{\rm{rms}}}}\left( {{\rm{helium}}} \right)}}{{{{\rm{V}}_{{\rm{rms}}}}\left( {{\rm{argon}}} \right)}}} \right],\) is close to: |
| A. | 3.16 |
| B. | 0.32 |
| C. | 0.45 |
| D. | 2.24 |
| Answer» B. 0.32 | |
| 10. |
For a series RLC circuit driven by voltage v = vmsinωt, the current is given by i = im sin(ωt + φ) and the power factor = __________ |
| A. | tanφ |
| B. | cos2φ |
| C. | cosφ |
| D. | tan2φ |
| Answer» D. tan2φ | |
| 11. |
For a series 'RLC' circuit driven by voltage v = vm sinωt, the current is given by i = im sin(ωt + φ), the impedance (Z) of the circuit = ___________.(Where 'X'c is capacitive reactance and 'X'L is inductive reactance) |
| A. | √[R2 - (Xc - XL)2] |
| B. | R2 + (Xc - XL)2 |
| C. | R2 - (Xc - XL)2 |
| D. | √[R2 + (Xc - XL)2] |
| Answer» E. | |
| 12. |
In a transformer, electric power is transferred from the primary coil to secondary |
| A. | Through air |
| B. | By electric field |
| C. | Through insulating medium |
| D. | By magnetic flux |
| Answer» E. | |
| 13. |
Consider the LR circuit shown in the figure. If the switch ‘S’ is closed at t = 0 then the amount of charge that passes through the battery between t = 0 and \(t = \frac{L}{R}\) is: |
| A. | \(\frac{{2.7EL}}{{{R^2}}}\) |
| B. | \(\frac{{EL}}{{2.7{R^2}}}\) |
| C. | \(\frac{{7.3EL}}{{{R^2}}}\) |
| D. | \(\frac{{EL}}{{7.3{R^2}}}\) |
| Answer» C. \(\frac{{7.3EL}}{{{R^2}}}\) | |
| 14. |
For a series RLC circuit driven by voltage v = vmsinωt, the current is given by i = im sin(ωt + φ), the average power loss over a complete cycle is given by 'P' = _________. |
| A. | V I tanφ |
| B. | V I cos2φ |
| C. | V I tan2φ |
| D. | V I cosφ |
| Answer» E. | |
| 15. |
In a step-up or step-down transformer, electrical power is transferred from one circuit to another without change in |
| A. | voltage |
| B. | current |
| C. | frequency |
| D. | capacitance |
| Answer» D. capacitance | |
| 16. |
A step up transformer has |
| A. | EMF per turn higher in secondary winding when compared to the primary |
| B. | EMF per turn equal in both primary and secondary windings |
| C. | EMF per turn higher in primary winding when compared to the secondary |
| D. | None of the above |
| Answer» C. EMF per turn higher in primary winding when compared to the secondary | |
| 17. |
AC power is expressed as __________. (Where 'i'm amplitude of the AC current and 'R' is circuit resistance) |
| A. | im2R |
| B. | im2R/2 |
| C. | imR2/2 |
| D. | imR2 |
| Answer» C. imR2/2 | |
| 18. |
If the magnetic field of a plane electromagnetic wave is given by \(B = 100 \times {10^{ - 6}}{\rm{sin}}\left[ {2\pi \times 2 \times {{10}^{15}}\left( {t - \frac{x}{c}} \right)} \right]\), Then the maximum electric field associates with it is (Take, the speed of light = 3 × 108 m/s) |
| A. | 6 × 104 N/C |
| B. | 4 × 104 N/C |
| C. | 3 × 104 N/C |
| D. | 4.5 × 104 N/C |
| Answer» D. 4.5 × 104 N/C | |
| 19. |
An ac voltage v = vm sinωt applied to a capacitor drives a current in the capacitor, i = ______________. |
| A. | im sin(ωt - π/2) |
| B. | im sin(ωt - π) |
| C. | im sin(ωt + π) |
| D. | im sin(ωt + π/2) |
| Answer» E. | |
| 20. |
A series AC circuit containing an inductor (20 mH), a capacitor (120 μF) and a resistor (60 Ω) is driven by an AC source of 24 V/50 Hz. The energy dissipated in the circuit in 60 s is: |
| A. | 5.65 × 102 J |
| B. | 2.26 × 103 J |
| C. | 5.17 × 102 J |
| D. | 3.39 × 103 J |
| Answer» D. 3.39 × 103 J | |
| 21. |
An AC voltage is applied to a purely capacitive circuit. The current in the circuit ______. |
| A. | lags the voltage by one-fourth of a cycle |
| B. | lags the voltage by one-half of a cycle |
| C. | leads the voltage by one-fourth of a cycle |
| D. | leads the voltage by one-half of a cycle |
| Answer» D. leads the voltage by one-half of a cycle | |
| 22. |
Capacitive reactance is equal to __________. |
| A. | ωC |
| B. | 1/(ωC) |
| C. | ω/C |
| D. | C/ω |
| Answer» C. ω/C | |
| 23. |
A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5 A and its efficiency is 90%, the output current would be: |
| A. | 50 A |
| B. | 45 A |
| C. | 35 A |
| D. | 25 A |
| Answer» C. 35 A | |
| 24. |
An ac voltage v = vm sinωt applied to a pure inductor L, drives a current in the inductor, i = _________ |
| A. | im sin(ωt - π/2) |
| B. | im sin(ωt + π/2) |
| C. | im sin(ωt - π) |
| D. | im sin(ωt + π) |
| Answer» B. im sin(ωt + π/2) | |
| 25. |
A transformer has 300 turns in its primary coil and 75 turns in its secondary coil. When the current in the secondary coil is 20 A, the current in the primary coil is |
| A. | 5 A |
| B. | 25 A |
| C. | 80 A |
| D. | 6.4 kA |
| Answer» B. 25 A | |
| 26. |
In an LC circuit (L-inductor and C-Capacitor), the frequency of oscillation is |
| A. | \(f = \frac{1}{{2\pi \sqrt {LC} }}\) |
| B. | \(f = \frac{1}{{2\pi \sqrt {L/C} }}\) |
| C. | \(f = \frac{1}{{2\pi \sqrt {C/L} }}\) |
| D. | \(f = {{2\pi \sqrt {LC} }}\) |
| Answer» B. \(f = \frac{1}{{2\pi \sqrt {L/C} }}\) | |
| 27. |
Lenz's law is in accordance with law of conservation of |
| A. | energy |
| B. | mass |
| C. | charge |
| D. | momentum |
| Answer» B. mass | |
| 28. |
A helium nucleus enters perpendicularly in magnetic field 'B' with velocity 'v', then magnetic force acting on it will be |
| A. | 2 Bev |
| B. | zero |
| C. | evB |
| D. | evB/2 |
| Answer» B. zero | |
| 29. |
Changing current in one coil induces EMF in another, this phenomena is known as |
| A. | EMF |
| B. | induced EMF |
| C. | self-induction |
| D. | mutual induction |
| Answer» E. | |
| 30. |
Turn ratio (r) for a step-up transformer is |
| A. | r = 0 |
| B. | r > 1 |
| C. | r < 1 |
| D. | r = 1 |
| Answer» C. r < 1 | |
| 31. |
Induced current can be increased by |
| A. | stronger field |
| B. | moving loop faster |
| C. | coil of less turns |
| D. | both a and b |
| Answer» E. | |
| 32. |
Magnetic field is 0.6T and rate of change of area is 0.8 m²/s when N=1, induced EMF would be |
| A. | 0.48V |
| B. | 0.44V |
| C. | 1.2V |
| D. | 2.1V |
| Answer» B. 0.44V | |
| 33. |
A metallic ring is attached to wall of a room. When North Pole of magnet is brought near ring, induced current in ring is |
| A. | zero |
| B. | clockwise |
| C. | anti-clockwise |
| D. | infinite |
| Answer» D. infinite | |
| 34. |
Induced current depends upon speed with which conductor moves and |
| A. | resistance of galvanometer |
| B. | resistance of galvanometer |
| C. | voltage of loop |
| D. | current of loop |
| Answer» E. | |
| 35. |
In alternative current generator, AC current reverses its direction |
| A. | 20 times per second |
| B. | 50 times per second |
| C. | once per second |
| D. | twice per second |
| Answer» C. once per second | |
| 36. |
EMF produced in conductor is known as |
| A. | EMF |
| B. | induced EMF |
| C. | deduce EMF |
| D. | both a and b |
| Answer» C. deduce EMF | |
| 37. |
Change of current of 1 A s-1 causes EMF of 1 V to be equal to |
| A. | 1 H |
| B. | 1 V m-1 |
| C. | 1:00 AM |
| D. | 1 J |
| Answer» B. 1 V m-1 | |
| 38. |
In system international, unit of mutual inductance is |
| A. | henry |
| B. | V s A-1 |
| C. | Wb |
| D. | both a and b |
| Answer» E. | |
| 39. |
Whenever magnetic flux linked with a coil changes, induced EMF in circuit will change |
| A. | for a short time |
| B. | for a long time |
| C. | forever |
| D. | as long as change in flux |
| Answer» E. | |
| 40. |
Transformer is being used in |
| A. | DC circuit |
| B. | AC circuit |
| C. | AC circuit |
| D. | both a and b |
| Answer» C. AC circuit | |
| 41. |
Alternative current generator is basically based upon |
| A. | amperes law |
| B. | Lenzs law |
| C. | Faradays law |
| D. | coulombs law |
| Answer» D. coulombs law | |
| 42. |
Square coil of side 16 cm having 200 turns rotating in magnetic field of 0.05 T with peak EMF of 12 V will produce angular velocity of |
| A. | 47 rad s-1 |
| B. | 49 rad s-1 |
| C. | 42 rad s-1 |
| D. | 48 rad s-1 |
| Answer» B. 49 rad s-1 | |
| 43. |
Electro motive force induced by motion of conductor across magnetic field is called |
| A. | EMF |
| B. | motional EMF |
| C. | static EMF |
| D. | rotational EMF |
| Answer» C. static EMF | |
| 44. |
Self-induced EMF is sometimes also known as |
| A. | induced EMF |
| B. | deduce EMF |
| C. | back EMF |
| D. | both a and b |
| Answer» D. both a and b | |
| 45. |
Device that converts electrical energy into mechanical energy is |
| A. | AC generator |
| B. | DC generator |
| C. | cell |
| D. | DC motor |
| Answer» E. | |
| 46. |
Dimensions of rate of change of flux are equivalent to those of |
| A. | voltage |
| B. | current |
| C. | 1/charge |
| D. | charge |
| Answer» B. current | |